Protein degradation inhibition by Nanomaterials
The lysosome–autophagy system and the ubiquitin-proteasome system (UPS) are the well-known mechanisms for removing the modified and aggregated proteins, and damaged organelles as cellular wastes. The cooperative function of autophagy and UPS systems function produce short-chain polypeptides that maintain the amino acid supply and energy balance of the starved cells, which is vital in maintaining the cellular homeostasis (Mizushima, Levine, Cuervo, & Klionsky, 2008; Nam, Han, Devkota, & Lee, 2017). It is shown that the diminished rate of intracellular protein degradation and autophagy, led to the misfolded proteins and non-functional macromolecules inside the cell, which are involved in the pathology of neurodegenerative disease associated with aging, such as Parkinson and Alzheimer (Jiang & Mizushima, 2014; Nah et al., 2015). Also, the dysregulated autophagy system impact on the innate immune response. Pro-inflammatory factors activity, cytokine/chemokine secretion, lymphocyte activity, and tracing antigen were associated with blunted autophagy response in some age-related diseases (Cuervo & Macian, 2014; Shi et al., 2012).
More than forty types of nanomaterials have been reported so far with modulating effect on cell autophagy, including diverse structural types of graphene, carbon-based nanotubes, gold particles, dendrimers, iron oxide, cationic liposomes, fullerene and its derivatives, silica, and α-alumina (Cordani & Somoza, 2019). Nanomaterials can influence the process of cell autophagy via multiple pathways. These compounds can have plausible applications in the detection and control of autophagy-associated diseases, especially those related to aging. Different nanomaterials mediate distinct mechanisms of autophagy based on their disparate chemical and physical particularity (Wei & Le, 2019). The mechanisms of autophagy modulation induced by nanomaterials can be categorized into three classes: oxidative stress induction, direct regulation of autophagic signaling pathways, such as Akt/mTOR, and alteration of the autophagy-related genes or proteins expression level (Zheng, Wei, Li, & Le, 2016).Table 3 summarizes some nanomaterials with autophagic modulating modulatory effects as anti-aging materials.